package com.example.forum.interceptor;


import com.example.forum.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 登录拦截器
 */
@Component
public class LoginInterceptor implements HandlerInterceptor {

    @Value("${forum.login.url}")
    private String defaultURL;
    /**
     * 前置处理 对请求的预处理
     * @throws Exception
     * @return true:继续流程  <br/> false: 流程终端
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //获取session
       HttpSession session =  request.getSession(false);
       if(session != null && session.getAttribute(AppConfig.USER_SESSION) != null) {
           //用户已登录 校验通过
           return true;
       }
       //校验URL是否正确
        if(!defaultURL.startsWith("/")) {
            defaultURL = "/" + defaultURL;
        }
       //校验不通过 跳转到登录页面
        response.sendRedirect(defaultURL);
       //终端流程
       return false;
    }
}
